Acquired a PDP11/44, but missing M7095

From: John Lawson <jpl15_at_panix.com>
Date: Wed Dec 11 11:52:00 2002

On Wed, 11 Dec 2002, Glen S wrote:

> A google search for M7095 turned up www.jtcomputer.com so I already sent an
> email earlier tonight inquiring about a M7095. Are they a decent place to
> do business with?

  I personally dunno yet - one of my two /44s has a bad data paths card in
the CPU, and I was going to call them, but haven't yet.

  Any other ListMembers done any business with J. T. Computers? for DEC
stuff?

>
>
> I didn't get any disk subsystems. The rules of the surplus department where
> I aquired the CPU dictate that disk drives be destroyed before systems are
> made available to the public.

   Sigh. Generally there's no *real* reason for this... just the "fix
everything with a hammer" solution. Too bad...


>
> The I/O cards that were installed were an M7521 DELUA ethernet, CMD
> CDU-720/TM SCSI, M7819 DZ11-A octal serial, Digital Pathways TCU-150 clock
> module?, M7258 LP11, Datasystems DLP-11.
>

   The Peripherals Handbook (I have the 1981 version) shows a bunch of
different LP11 systems, and most of them are big clunky line printers that
would typically be used in a large multi-user machine. Most of them come
with that 30 meter I/O cable.

  BTW - how many slots / backplanes are curently installed? How many free
slots? How many BUs Grant cards are in open slots? It is also possible
that you will need access to the underside of the machine at some time (to
attach/remove NPR jumpers) so don't mount it where that would be
difficult, until you have the System stable and configured the way you
want it.


> The CPU came in a rack that is about three times the height of the the
> PDP11/44 and about 1.25x as wide.

   These are rather bulky, unless you have the RL02 drives, or the RL02
and RAxx that came in it. The it's REALLY heavy. The DEC cabs are built
very nicely, but it's probably more space-efficient to put the system in a
standard 19" rack (DEC H960-type if you can find one). As long as the rack
slides can attach at the front and back, any rack will work that will
support the eventual weight. Or, if you're going to run the system with
small SCSI drives only, then it can just sit on the table. One of mine has
a sheet of 1/8" plexiglass instead of the metal top cover, so you can see
in when it's running.

> degress and I don't think I have any compatible outlets in my house so that
> is yet another challege to solve.

  Not too bad - get a 15A plug from any of the Home DIY places or a big
hardware store. Take off the (should be attached with various screws and
clamps) existing 20A plug and attach the 15A one. Remember that the the
Black (hot) wire goes to the Brass terminal, the White (neut) wire goes to
the Silver terminal, and the Green (gnd) wire goes to the green (or black)
Ground terminal.

   Your CPU, configured as it is now, will draw maybe 6 or 7 amps from the
wall at 120V, so you're good to go.

>
> If I do get the CPU running, then I'll have to figure out what software I
> should try to run on it. I don't really know much about PDP11 software yet.
>

  I would suggest downloading the Supnik suite of emulators
(www.simh.trailing-edge.com) to get a flavor of the various OSes available
for the 11/44 series. Once you have the SCSI card running (very fortunate
find, BTW!) then you can begin building the system from there, as well as
using the simulators to collate files for installation on the /44.


  Cheers

John
Received on Wed Dec 11 2002 - 11:52:00 GMT